1. Field of the Invention
The invention relates to a program calling method, more particularly to a Java applet calling method which is applicable to a Java card virtual machine structure.
2. Description of the Related Art
As applications on a mobile terminal device have developed to have more variety, and as complexity in the aspect of business continues to increase, services provided on the mobile terminal device have become more diverse.
Conventional personal service certification identity terminals, such as subscriber identity module (SIM) cards, identification (ID) cards, bank cards, etc., all belong to a Java card operating system (COS) smart card which conforms with the Java card and Java SIM structure and which has a single input/output (I/O) port interface. These smart cards are categorized as a passive element, and are to be called by the mobile terminal device through protocols. Therefore, if one Java applet of a smart card is desired to be executed in another Java applet, which is running on a Java card virtual machine in the same smart card, a shareable interface object (SIO) is required to be practiced. In other words, calling of a Java applet is currently executed through an instruction invocation by the mobile terminal device or an external card reader device. If it is desired to execute calling between Java applets, the current regulations associated with a Java applet should be modified. However, since the current Java card and Java SIM structure have been practiced for decades, and more than hundreds of millions of the smart cards have been issued to the market, it is impossible to modify the regulations. Moreover, the practice of the SIO interface also incurs security concerns. In addition, current application regulations, which are associated with security of bank cards, published by many international organizations do not include the invocation regulations designed in the SIO, let alone calling between Java applets.
Accordingly, how to perform calling between Java applets under the premise of not modifying the current Java applet regulations is the focus of the present invention.